Modified infratemporal fossa approach via lateral transantral maxillotomy: a microsurgical model.

BACKGROUND: Lateral approaches have traditionally been used to gain access to lesions of the infratemporal fossa (ITF). However, dysfunction of the facial nerve secondary to its translocation, conductive hearing loss, and dental malocclusion because of mandibular head resection or dislocation are significant limitations associated with some of these approaches. Although facial nerve translocation and extended maxillotomy approaches avoid some of these drawbacks, they are invasive and require extensive osteotomies and facial incisions. To avoid these potential complications and maintain an extranasal/extraoral exposure, we studied the use of a lateral and posterior extension of an anterior transmaxillary approach to the cavernous sinus.

METHODS: The study was performed on 12 cadaver specimens and two dry skulls. An initial nasolabial fold incision, followed by an en bloc osteotomy of the anterior and lateral maxilla provides a window into the medial ITF. After osteotomy of the pterygoid plate and the posterior maxillary wall, the floor of the middle fossa is exposed to reveal the mandibular and maxillary divisions of the trigeminal nerve exiting their respective foramina. The floor of the middle fossa is then drilled postero-medial to the foramen ovale to gain access to the course of the C3-C4 portion of the petrous carotid artery and the eustachian tube. The upper two-thirds of the clivus and the pituitary gland are accessed after drilling of the floor of the sella turcica and form the posterior limit of this exposure.

RESULTS: The technique offers a trajectory to the medial ITF and skull base that does not necessitate palatal splitting or opening of the nasopharynx. The anterior route avoids temporomandibular joint disruption, and spares the lacrimal apparatus and all branches of the facial nerve. In addition, the reflected pterygoid muscle can be used as a vascularized flap for closure of the skull base defect.

CONCLUSION: The approach may be an alternative less invasive approach to the ITF and may be suitable for ITF lesions that have minimal lateral or intracranial extension.